Combined radio and intercommunicating set



Oct. 30, 1951 w. w. GARSTANG COMBINED RADIO AND INTERCOMMUNICATING SET 2 SHEETS-SHEET 1 Filed Feb. 24, 1947 INVENTOR.

W. W. GARSTANG COMBINED RADIO AND INTERCOMMUNICATING SET Oct. 30, 1951 2 SHEETS-SHEET 2 Filed Feb. 24, 1947 IN V EN TOR. flaw wf/zgm,

Hum Hm WM BY Hun 3; in F mm Patented Oct. 30,1951

UNITED STATES PATENT OFFICE COMBINED RADIO AND' INTEROOMMUNL OA-TING SET Application February 24, 1947, Serial No. 730,479

Claims. 1

Thepresent invention relates to improvements iii-radio receiving .sets, and has for one of its objects that of providing means whereby the radio receiving set may form a part of an intercommunicating system.

Afurther object of the invention is to provide a-systemin which a radio receiving set may, without interfering with the normal operation of;the receiving set for radio reception, provide atoleast one station of an intercommunicating system..

a A further object of the invention. is that of providing a system whereina radio receiving set may provide at least one station of an intercommunicating system, in which system means are provided wherebywhen the or any of the slave stations is placed in communication with the ffrnaster station comprised in the radio receivinggset, the radio reception will be shut off in event the radio receiving set is acting as a radio receiver.

, A'further'object of the invention is to provide means whereby the radio receiving set may be used-,as -a master station. for selective. communication ,withone or more slave stations.

Further objects and advantages of the invention will appear more fully hereinafter in the appended; specification and claims.

, For the purpose of disclosing the invention, I haveli-llustrated an embodiment thereof in the accompanying drawings, in which:

Fig-1 ispgiiagrammatic view of a circuit disclosing one''mbodiment of the invention; and

Fig; 2is a diagrammatic-view of a circuit disclosing a modification of the embodiment shown crystal detector stage 3 is coupled with a first audioamplifier 4, which in turn is coupled to aristepedown transformer, including the primary winding 5 and a secondary winding 6.- The stepdown transformer in turn is coupled to a stepuptransformer, which transformer includes a primary- 1 and a secondary 8. This step-up transformeris coupled to the input of an audio amplifiertube III, the output of which is connected through a condenser .I I .to the grid circuit a of an outputtube l2- The outputtube I 2 in turn is coupled through a step-down transformer [3, which is provided with a primary winding M and a secondary winding I5 to the coil 16 of the speaker ll of the radio set.

Associated with the radio receiving set, above described, is a control switch l8 provided with three control switch arms I9, 29 and 2|. These switch arms are mechanically connected sothat the three switches will move in unison. The

three switch arms may be movedfrom a first po' which may be designated as the radio position,

and in this position the arms I9, 26 and 2| respectively engage contacts 28, .29 and 30. In addition to the above control switch, there is provided preferably in the radio set, a selector switch 3| through the medium of which any one of the hereinafter described slave stations may be selected for the purpose of communication with the radio receiving set. This selector switch includes a movable switch arm 32 adapted to be moved to any one of the selected contacts 33, 34, 35 or 36, this number of contacts being provided in the system illustrated to accommodate four slave stations.

As indicated, the system illustrated is adapted to accommodate four slave" stations 31, 3B, 39 and 49. The slave station 31 includes a speaker and a speaker coil 4| which is connected to a. contact 42, adapted to be engaged by a switch arm 43. The opposite terminal of the speaker coil 4| is grounded. The switch arm 43 is normally in engagement with a contact 44.

Likewise, the station 38 is provided with a speaker coil 45, one terminal of which is ground ed and the other terminal of which is. connected'to a contact 48 adapted for engagement by a switch arm 41, which arm also is normally in engagement with a contact 48.

Station 39 has its speaker coil 49 grounded, with one terminal connected to a contact 50 adapted to be engaged'by the switch arm 5|, which is also normally in engagement .with the contact 52;

Station 40 has its speaker coil 53 grounded, as are the other speaker coils, and a terminal connected to contact 54 adapted to be engaged by the switch arm 55, which is normally in engagement with contact 56. The term normally is used with respect to switch arms 43, 41, 5| and 55 as describing the position these switch arms occupy, when the slave stations are in a condition of reception of signals from the radio set and in normal operation of the system. These switches are normally biased through spring other means into receiving position.

One terminal of each of the two windings 6 and 1 is grounded, as at 56, and likewise one terminal of each of the two windings I and H5 is grounded as at 58. The opposite terminal of the secondary winding 6 is connected to switch arm I9, while the opposite terminal of the winding 1 is connected to the switch arm 2|. The opposite terminal of the winding I5 is connected to the switch arm 20, while the opposite terminal of the winding I6 is connected to the contact 24, this terminal of the winding It being likewise connected to the contacts 29 and 26.

The contact 28 of the switch I8 is connected to contact 44 of the first slave station 31, while thecontacts 21 and 30 of the switch l8 are connected to the switch arm 55 of the last slave station 40.

Contact arm 43 of the first slave station is connected to the contact 48 of the second station, while the contact arm 41 of the second slave station is connected to the contact 52 of the third slave station. Contact arm 5| of the third slave station is connected to contact 56 of the fourth slave station, while contacts 42, 46, 50 and 54 of the respective slave stations 31, 38, 39 and 49 are respectively connected to the contacts 33, 34, 35 and 36 of the selector switch 3|.

By the arrangement of the step-down trans former; including the primary and secondary windings 5'and 6, the impedance of the first audio stage is stepped down to an impedance which is equivalent of the Voice coils 4|, 45, 49 and 53 of the stations 31, 38, 39 and 40.

For the purpose .of illustration, we will assume that the switch arms I9, 20 and 2| are placed in radio reception position and that the radio is operating. Under these circumstances, one terininal of the winding 6 will be connected through the switch arm I9, contact 28, the switch arms 43, 41; 5| and 55, which are normally in the position indicated, and back to contact 30 of switch It through switch arm 2| to the terminal of the primary 1. At the same time, the terminal of the secondary I5 of the transformer |3 will be connected through a switch arm 20, contact 29 to the terminal of the speaker coil l6. Therefore, the radiocircuit will be established and the radio will be in operable condition for radio reception. We will assume now that it is the desire of slave station 31 to communicate with the operator of the radio. Under these circumstances, the operator of the slave station 31 will move the arm 43into engagement with the contact 42. Therefore, a speaking circuit of the radio will be established from ground through the speaking coil 4| across switch arm'43, across switch arms 41, 5| and 55 to contact 30 and thence across switch arm 2| to the primary 1 and thence back to ground at 56. The radio speaker coil IE will be energized from the speaking coil 4|. The effect would be the same, in event that any one of the other switches 41, 5| or 55 is moved to a sending position.

4 If the operator of the radio merely desires to receive a message, he need not manipulate either switches H3 or 3|. If, however, the operator of the radio wishes to communicate back with station 31, the switch I8 is operated to move the switch arms respectively in contact with con-v tacts 22, 23 and 24 and at the same time, the operator will move switch arm 32 in engagement with contact 33. Therefore, as soon as the'operator at station 31 has communicated and released his switch 43, or moved the same back to its normal or listening position, the winding |5 of the transformer |3 will be connected through switch arm 20 and switch arm 32 to the coil 4| of the speaker 31, which in turn is grounded, it being remembered that the opposite terminal of the coil l5 is likewise grounded. At the same time, the speaker coil I6 will be connected through switch arm 2| to the primary 1, and secondar 6 will be connected to ground through switch arm I9 and thus be rendered inoperative, so that the operator at the radio loud speaker may have return communication with the operator at the slave station 31. 7

If it be desired to place the radio in nonradio receiving condition and at the same time place the same in intercommunicating position, the radio operator would move the switch 8'to intermediate position, wherein the switch" arms I9, 20 and 2| are in engagement with contacts 25, 26 and 21. Under these conditions, assuming that station 31 wished to communicate with-the radio station, by closing switch arm 43 men gagement with the contact 42, the primary 1 would be connected in a circuit from groundto the speaker coil 4| across the switch 43, across switches 41, 5| and 55 to contact 21 and across switch arm 2| to the primary Winding 1. At the same time, the terminal of the secondary |5 is connected across switch arm 20 to contact arm 26 and thence back to the terminal of winding l6 and the circuit including the tubes [0 and I2 will operate the speaker |1.

It is thus apparent that by the above construction, I have provided a system whereby a radio receiving set may provide one station of an intercommunicating set, in which the other sta tions may at any time, during the operation of the set for radio reception, interrupt the radio reception for the purpose of talking to the operator of the radio and the operator of the radio may then have return communica with the initiating station. At the same tiliie, inevent the radio is rendered inoperative for radio reception, communication may be made betweenthe various stations of the intercommunicating set.

In the circuit shown in Fig. 2, I have illustrated a modification of a system illustrated in Fig. 1. In the modification, I have provided a second radio which may be used as a radio receiving set and which at the same time, maybe used as one station of an intercommunicating set, the other station being provided with an audio circuit including the first amplifier tube 59, the second audio amplifier tube 69, the power output tube 6| and the speaker 62. Likewise, the second radio set includes a first amplifier tube 63 a second amplifier tube 64, a power output tu'be65 and a speaker 66. Interposed between the first audio amplifier tube 59 and a second-amplifier tube. 60 of the first radio set is a step-down transformer 61 including the primary coil 63 coupled with the first audio amplifier tube 59',"the secondary coil 69 coupled with the primary coil 10 of a step-up transformer with the secondary coil -to any one of three positions.

II coupled to the second audio amplifier tube 69.

' For operating the system,in order that either or-both of the radio sets may be used for radio reception, and if desired, as intercommunicating sets, I provide with the first radio, a switch I6 including the movable switch arms 11, I8 and I9 mechanically connected, so that they will operate in unison. These switch arms are movable In the first position, switch armsII and I8 will engage contacts 89 and BI respectively, and switch arm I9 will engage the dead contact 82. In the second position, the arms 11, I8 and I9 will respectively engage contacts 83, 84 and 85, while in the third position, arms 17, I8 and I9 will engage contacts 86, 8! and 88 respectively.

The second radio is provided with a similar switch 89 having switch arms 99, SI and 92 mechanically connected, so that they will be moved in unison and when the switch is in its first position, arms 99 and 9| will engage contacts 93 and 94 and arm 92 will engage the dead contactv 95. In their second position, arms 99, 9| and 92 will engage contacts 96, 91 and 98 and in their third position, arms 99, 9| and 92 will respectively engage contacts 99, I99 and I9I.

Terminals of the windings 69 and I9 and the windings I4 and I5 are connected together, these windings likewise being grounded respectively, as at I92 and I93. The opposite terminal of the winding 69 is connected with switch arm 17, while the ungrounded terminal of the winding I9 is connected with switch arm 9|. The ungrounded terminal of the winding I4 is connected with Switch arm 90, while the ungrounded terminal of winding I5 is connected with switch arm I8. Contact terminals 86, I99 and 91 are interconnected, asare likewise contacts 99, 81 and 84 innected to switch arm I9 and contact 8I the coils I95 and I96 being grounded at I9I.

Likewise, the power output tube 95 of the second radio is connected to the primary winding I98 of a transformer, the secondary I99 of which .is connected to the voice coil II9 of the speaker 69. The opposite terminal of this secondary I99 is connected to contacts 98 and IN, while a terminal of the winding H9 is connected to switch arm 92 and contact 94. These windings I99 and H9 are grounded as at III.

In the operation of the embodiment illustrated in the circuit shown in Fig. 2, we will assume that the second radio is in the receiving position and it is desired that the operator of the first radio wishes to communicate with the operator of the second radio. With the second radio in the receiving position, switch arms 99, 9| and 92 will be respectively engaging contacts 99, I99 and IN and with the first radio in sending position, switch arms 71, I8 and 19 will be respectively engaging contacts 89, 8| and 82. Accordingly, the speaker coil I96 will be connected to contact 8| across switch arms 18 through the primary I5 and thence by ground to the opposite side of coil I96. Therefore, the primary I5 will be energized and with the contact engaging contact ml, the coils I99 and I I9 will be energized and communication will be .to the speaker 69, the coils 69- and I4 being grounded to ground out the radio reception. It is obvious that a reverse situation could be occasioned in event the first radio were in playing or receiving position and the second radio had its switch placed in sending position. When the switches 86 and 89 are in receiving position instead of radio position, the radio is cut out and.the two devices become merely intercommunicating sets.

I claim as my invention:

l. A radio system comprising a radio .receiving system, including a radio frequency source, an audio circuit having a first audio amplifier having its input side connected to said frequency source, a second audio amplifier, a first speaker having a speaker coil, a first transformer having its primary connected with the output side of said sec-ond audio amplifier and its secondary connected with said first speaker coil, a second transformer having its primary connected with the output sideof said first audio amplifier, a third transformer having its secondary connected to the input side of said second audio amplifier, a plurality of secondary speakers each having a speaker coil and switching means operatively connected with each of said secondary speaker coils, each of said switching means in one position connecting the secondaryof'the second transformer with the primary of the third transformer and in its second-position connecting its associated speaker coil with the primary of the third transformer. I 1

2. A radio system comprising a radio receiving system, including a radio frequency source, a

necting the secondary of said first transformer with the primary of said second transformer, including a switch having a switch arm connected with one terminal of the primary winding of said second transformer and a contact connected with a terminal of the secondary winding ofthe first transformer, a second speaker having a speaker coil and a second contact on said switch connected with said speaker coil, said switch arm when engaging said first contact connecting terminals of the secondary of the first transformer and of the primary of the second transformer and when engagement with the second contact connecting the terminal of the primary of the said second transformer with the speaker coil of said second speaker, the other terminal of said speaker coil being grounded and terminal of the primary of the second transformer being grounded.

3. a A radio system comprising a radio frequency source, a first audio amplifier connected to said radio frequency source, a first transformer having its primary connected to the output side of said first audio amplifier, a second audio ampliass sari? flea: a second transformer having? its: secondary connected: to the inputside of: said second audio amplifier,- .a third" transformer'ha,vingits, primary connected =.to'-the output side of said second-audio amplifier; afirst speaker having a--speaker coil connected .to the-"secondary: of-- said third trans- .former, ,-means.for connectingtheprimary of.- said first: transformer with the secondary-of said'secondstransformer includinga first "SWitChliEI-XQ a second switch, said first switch having a: switch armeconn'ected; to one terminal of the primary of saidlsecond transformer and a contact connected to the switch arm ofsaid second switchrsaid .secondswitch: having a contact''= connected" to a cdntactzof a'-third switch and a s'econd contact connected to the speaker coil-of aisecond speaker, said third switch havinga-contact-arm connected to the terminal of the secondary of the first transformensaid first,.second and third switches when their first positions connecting. a terminal' ofl the secondary. .ot: the first transformer with a terminal of the primary of the second transformer, said first and second switches when in theirsecond position connecting the' primary of saidsecond transformer with the speaker coil of said second speaker, said third switch when in its second position grounding a terminal of the primary -.of thefirst-transformer.

4; A radiosystem comprisinga-radio receiving system-, ,including-' a' radio'frequency source, an

7 audio circuit-having-a first audio amplifier connee-ted to'said frequency source, a second audio amplifier, afirst speaker having a speaker coil,

a first transformer having its primary connected to the output side of-said second audio amplifier and its'secondary. connected to the first speaker coil, al second transformer having its primary connected to the output sideof the first audio amplifier, a third transformer having its secondar-yc connected-totheinputside-of said second audioamplifier, a second speaker having a speaker coil; a first switch having a switch arm connected to the primary of said-third transformer; a first contact and a second contact, a second switch havingaa switch arm: connected t'o terminal-'- of 1 the sec'ondary-of the second: transformer-and the switch armofsaid: first switch when in engagement with the secondcontaet" thereof connecting the coil of thesecond speaker with the primary ofsaid-thirdtransformer-and v said secondswitch armwhen-moved out-of en?- 7 gagement with this contact disconnec =ting-.- the the secondary of said second-transformer and'a contact connected to the secondary. of said "secs ond transformerand a; contact connected with saidafi-rst contact -of said first switch 'thesecond contact of a said first 1 switch being; connected to the speaker coil ofsaidsecond speakerthe switcharmof said first switch when .in engagement with the first contact thereof andsaid switcharm of the second switch when inengagement with itscontact connecting. a terminal of the primaryofthe thirdtransformer with a" terminal of the secondary of the secondqtransformer from-the firstacontactaof ther-firstgswitch. 5 .--A -radiosystem-eomprisingla radio frequency source a-firstaudio amplifier; connected.- to; the output side'of said frequency 'source,=a-first transformer having its primary connected to the outaudio ampl'ifler, a second transformer having-wits secondary connected-to the input side ofsaid second-audio amplifier, athird-transformer having its primary: connected to the output sideg'of said second audioamplifier. a? first speaker hav- -ing-;- a--.speaker coil, 5a second-= speaker having a speaker coil; a firstand 1 a secondswitch eachhavrin -a first and-'a sec'ond position, said first switch' in its first position connectingithe; secondary'of saidfirst transformer with thefprimary of' said second transformer and saidsecOnd SWitch -Whcn inits first 'positioniconnectin'g, the-firstaspeaker coil with the secondary ofthe-thirdtransformer,

said first switch when in its :second "position connecting: the second speaker coil with the-primary of said second ct'ransformemlsaid second s-witchl-in its-"second position connecting the secondary of theathirdtransformer with the second speaker coil and a third switchwhen closed, with the first and second switches intheir second position; connecting said firstspeaker coil with the primary of the second transformer.

WrGARSTAN'G;

REFERENCES CITED The following references-are of r'ecorddn -the file of this: patent:

' UNITED STA'iES FATENT'S 

